Precision hammer



Dec.'vr l2, 1950 A. A. BAMBERGER 2,533,988

PRECISION HAmaER Filed April 22, 1947 2 Sheets-Sheet l.

ma? @M ATTORNEY Dem 12 1950 A. A. BAMBERGER 2,533,988

PRECISION HAMMER Filed April 22, 1947 2 Sheets-Sheet 2 INVENTOR ATTORN EY Iatented bec.

UNITED STATES 2,533,988 PRECISION HAMlWER Alfred A. Bamberger, Flushing,

N. Y., assignor to Speedo Manufacturing Co., Inc., New York,

Application April 22, 1947, serial No. 743,086'

(ci. 12s- 33) 3 Claims.

This invention relates to a precision hammer. More particularly it is concerned with hammers of the type in which the head is reciprocated by the repeated inpact of a cam operated member driven by a flexible shaft.

An object of this invention is to provide a hammer of the character described in which the head member of the device receives on a rear portion thereof, the repeated impact of a cam actuated slidable member which is urged toward said head member by a spring member together with improved rotary adjusting means mounted on the device for regulating the tension of said spring member.

A further object of this invention is to provide in a, device of the character described a plunger casing together with a plunger disposed for reciprocating movement therein, together with spring means for urging the plunger in one direction and a rotatable, non-slidable sleeve on the plunger casing which engages a slidable member within the plunger casing and in abutting contact with said spring member whereby rotation of said sleeve imparts longitudinal movement to the slidable member and thereby determines the biasing action of the spring member with respect to the plunger.

Still another object of this invention is to provide a hammer comprising a plunger casing having a reciprocating hammer head extending from one end thereof and having the other end thereof provided with a bearing nut through which passes a rotatable, non-slidable shaft for imparting reciprocating motion to a plunger member disposed within the plunger casing and coaxial with the hammer head, together with a sleeve nut threaded externally at either end thereof and received on one end in the bearing nut, the other end being adapted to receive various types of couplings for interconnecting flexible shafts to said rotatable, non-slidable Shaft.

Still a further object of this invention, is to provide a compact and durable device of the character described which shall .be relatively inexpensive to manufacture, easy to manipulate, which shall be smooth and positive in operation, and yet practical and eihcient to a high degree in use.

Other objects of this invention will in part be obvious and part hereinafter pointed out.

'Ihe invention accordingly consists in the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter described,

2 and of which the scope of application will be indicated in the following claims.

Fig. 1 is an axial cross sectional view of the device embodying the invention;

Fig. 2 is a cross sectional View line 2-2 of Fig. 1;

Fig. 3 is a cross sectional View taken on the line 3-3 of Fig. 1;

Fig. 4 is a cross sectional View taken on the line 4-4 of Fig. 1;

Fig. 5 is an elevational View of the connector portion of the device embodying the invention;

Fig. 6 is an axial sectional view of a flexible shaft connector assembly portion of the device embodying the invention and illustrating a modification thereof; z

Fig. 7 is an axial sectional view similar to that shown in Fig. 6 and illustrating a modification thereof;

Fig. 8 is an axial sectional View similar to that shown in Fig. 6 and illustrating another modi cation thereof; and

Fig. 9 is a cross sectional view taken on the line 9-9 of Fig. 1.

Referring now in detail to the drawing, l0- designates a device of the character described.

taken on the The same' comprises a tubular casing II havingv an 'internally threaded portion I2 at the forward end thereof and 'having screwed therein a tapered housing I3 coaxial with the casing. The hammer housing I3 comprises a base-portion Ill of reduced diameter which is externally threaded and engages 1the threaded portion I2 of the casing II. The housing I3 is formed with an vaxial bore i5 from which extends rearwardly,

a communicating recess I6 of enlarged diameter.:

A tool holder Il is mounted for slidable movement within the bore I5. The tool holder I] comprises an enlarged rear portion IS which is slidably received in the recess I6 and comprises an end wall IBa which projects outwardly of the recess I5. The enlarged rear portion I8 of the tool holder is formed with a transverse opening I9 in which is received a pin 2l), the outer end portions of which projects on `either side of the enlarged portion I3. The projecting portions of the pin 2li are received within aligned op'en,

ings 2l formed in opposite sides of the base portion I4 of the housing I8. The openings 2i are of a diameter vpermitting limited longitudinal movement of the tool holder I1 in either direc-` tion. A coil spring 22 is mounted on .a reary portion of the tool holder Il and is disposed in the recess I5 betweentheforwardend .of the recess and the enlarged rear portion I8 ofthe tool holder. The spring 22 normally urges the tool holder to its rearmost position, as determined by the pin 20. The forward end of the tool holder I1 is formed with an internally threaded axial recess or socket 23 which receives an externally threaded rod or point 24.

A plunger or hammer 25 coaxial with the tool holder |1, is mounted for slidable movement within the plunger housing II. The plunger 25 comprises a front wall 26 disposed opposite the wall I8a. of the tool holder. The plunger 25 is formed with a longitudinal guide slot 26a on a Wall thereof, in which projects a guide member 21 secured to the plunger housing I I. The plunger 25 is further formed with an axial recess 28 opening on the rear end thereof and formed with screw threads 29. Disposed with in the recess 28 of the plunger is a camV member 3U which comprises a helically cut rearward face 3I. The cam 39 is further formed with an internally threaded axial opening 32 into Iwhich is screwed the threaded end portion of a rotatable, nonslidable shaft 33. A cam follower 34 is rotatably and slidably disposed on the shaft 33 and comprises a helically cut forward face 35 which is complementary to the face 3| of the cam 30= and a flanged portion 36 on the rear end thereof. The cam follower 34 is formed with an externally threaded portion 31 adjacent the flange 36, which is received in the threaded portion 29 of the plunger 25, the ange 36 bearing against the rear end of the plunger 25.

The plunger housing II further comprises a rearwardly extending cylindrical wall 38 of reduced external diameter forming a forward shoulder portion 38a. 'Ihe wall 38 of the housing |I is formed with a pair of longitudinally extending, aligned slots'39 on opposite wall surfaces thereof. The wall 38 further comprises an internally threaded portion 49 on the rear portion thereof. A bearing nut 4| is screwed into the 'wall 38. 'Ihe bearing nut 4| comprises a cylindrical wall 42 comprising an externally threaded outer surface 43 which engages the threaded portion 40 of the wall 38. The nut 4| further comprises an outwardly turned flange 44 at the rear end thereof which abuts the end of the wall 38. 'Ihe bearing nut 4| also comprises an inwardly turned flange bearing portion 45 formed with a through opening 45a in which is journalled a rear portion of the rotatable, non-slidable shaft 33. The inner surface of the wall 42 of the nut 4| is internally threaded to receive a sleeve nut 46 formed with a through axial opening 46a for receiving the shaft 33. The sleeve nut 46 comprises an annular wall 41 abutting the flange 44 of the bearing nut 4| and from one side of which extends an externally threaded sleeve portion 48 which is screwed into the internally threaded portion of the bearing nut 4|. An externally threaded sleeve portion 49 extends rearwardly from the wall 41. The shaft 33 comprises a collar 50 secured thereon. The collar 50 is disposed with its forward side in contact with the flanged portion 45 of the bearing nut 4| and sleeve portion '48 of the sleeve nut 46 bearing against the rear side of the collar 50 thereby preventing longitudinal movement of the shaft 33.

A rotatable, adjusting sleeve having an internally threaded surface 52 is disposed over the wall 38 between the shoulder 38a'and the flange 44, substantially flush with the outer surface of the plunger housing I I. The threaded surface 52 terminates short of the end of the sleeve 5|. An adjusting nut 53 is slidably and non-rotatably mounted on the shaft 3. The nut 53 comprises a central opening 54 through which the shaft 33 passes and from which extends an enlarged recess 55. Wing portions 56 extend radially from opposite sides of the recessed portion 55 and comprises threaded outer surfaces 51. The outer end portions of the wings 56 are disposed in the slots 39 in the wall 38, the threaded surfaces 51 projecting above the outer surface of the wall 38 and engaging the threaded surface 52 of the adjusting sleeve 5|. A coil spring 51a is mounted on the shaft 33 bearing disposed between the ange 36 and the recess 55 in the :collar 53. A clamping ring 58 is disposed between the unthreaded inner surface of the adjusting sleeve 5| and the outer surface of the wall 38.

The shaft 33 extends rearwardly through the sleeve nut 46, projecting beyond the sleeve portion 49 thereof. A threaded axial recess 59 is formed in the rear end portion of the shaft 33 and receives therein a coupling member 60. The coupling member 50 comprises a threaded forward end portion 6| which is screwed into the threaded recess 59 of the shaft 33@ The rear end of the coupling is formed with an axial bore 62. A longitudinal slot 63 formed in member 69 communicates with the bore 62.

A sleeve 64 is concentrically mounted with respect to the coupling member 60. The sleeve 64 comprises an internally threaded forward end portion 65 which is screwed on the externally threaded flange 49. Extending from the rear end of the sleeve 64 is an enlarged annular rear end portion 66. The wall of the annular portion 66 is formed with a recessed through opening 61 in which is seated a ball 68. The ball 68 is of a diameter such that it projects slightly beyond the outer and inner surfaces of the annular portion 66. A split spring sleeve 69 is disposed about the outer surface of the annular portion 66, and is formed with a transverse through opening 18 of a lesser diameter than that of the ball 68. The sleeve 66 overlies the outer wall of the annular portion 66 with the upper surface of the ball 68 received in the opening 10. The sleeve 64 receives the end portion of a flexible rotary shaft assembly 10a. The assembly 19a comprises a cylindrical head member 1I which is formed with an annular groove 12 on the circumference thereof. The member '1| is formed with an axial through opening 13 in which is received the rotary flexible shaft 14. The end portion of the shaft 13 comprises an upstanding rib 15. The end of shaft 14 is received in the axial bore 62 with the rib 15 engaged in the slot 63.

In using the device I0, the assembly 18a is connected to the sleeve 64 by inserting the member 1| in the annular portion 66 and moving it forwardly until the ball 68 engages the groove l2 in the member 1|. The split sleeve 69 will maintain the ball 68 in this position. The end of the shaft 14 engages the coupling member 69 at-y tached to the end of the shaft 33. The shaft 33 being rotated by the rotating flexible shaft 14, imparts rotary movement to the cam member 30 fixed thereto and disposed within the plunger 2 8. As the cam 3c rotates, its heneauy cut face 31, which is opposed to the helically cut face 35 on the cam follower 34, will progressively move the cam follower inwardly against the biasing action of the spring 51a. When the toe of the cam follower 34 just passes the toe of the cam 3D, the cam follower will b e instantly urged outwardly by the coil spring 51a. Since the plunger 25 is screwed on the cam follower 3.4. its axial moye-` ment will follow the movement of the follower. Accordingly, the outward movement of the cam follower will produce a similar outward movement of the plunger 25. The front wall 25 of the moving plunger will produce a sudden impact on the rear wall Ita of the tool holder l1, moving the tool holder l? outwardly against the action of the spring 22. The movement of the tool holder I1 will be limited by the pin 20. The spring 22 will restore the tool holder l1 to the normal rearward position immediately after the retraction of the plunger 25. Upon continued rotary movement of the shaft, the cam 30 will repeat its action with respect to the cam follower and the associated plunger. As a result the tool holder il will have a staccato, reciprocating ac- "tion The hammer I1 is provided with a remova- "ble, pin 24 which may be replaced by other pins selected for the particular type of work tovbe done by the device.

The action of the tool holder i1 may be regu- Y lated as to its force of impact. By rotating the sleeve 5l, the nut 53 is moved longitudinally within the slots 39 in the wall 38. The position of the collar 53 in turn determines the biasing action of the spring 51a. It is thus possible to regulate the action of the tool holder by simply rotating the sleeve 5| in either ldirection to produce a desired type of impact.

The device Il! may be interconnected to various types of flexible shafts by modified coupling constructions. ln Fig. 6 is shown a modified form of shaft coupling. The same comprises a member 16 formed with an axial through opening 11 and a communicating longitudinal slot 18 at one end thereof. The other end of the member 1B is internally threaded to receive the threaded end 19 of a coupling member 80. The other end of the coupling member 80 also comprises a threaded portion 86a on its opposite end which is engaged in the threaded bore portion 59 of the shaft 33. The shaft 14 having a rib 15, is connected to the member 'i6 in the manner previously described. A concentric sleeve 8l having an internally threaded end portion 82 is screwed on to the threaded flange 49 of the sleeve nut 45.

The coupling shown in Fig. '7 is similar to that shown in Fig. 6 except that it is modified toreceive a flexible shaft 14a formed with a threaded axial recess 82 which is engaged by the threaded portion 19 of the coupling 80.

In Fig. S is shown a coupling assembly wherein the shaft 33 has a threaded connectorrod 83 screwed into the threaded recess 59. A tubular casing 34 comprising an internally threaded end portion 85 is screwed on to the threaded flange 4S of the sleeve nut 45. The opposite end of the casing 84 is formed with a through opening 86. This form of coupling is adapted to receive a flexible shaft having a chuck portion which is engageable with the projecting end of the connector rod 83. A conventional fitting on the `flexible shaft snaps into the opening 86 on the Y.casing B4 thereby retaining the flexible shaft in engaging relationship with the shaft 33 through the rod 83.

It will thus be seen that there is provided a device in which the several objects of this invention are achieved, and which is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention I claim as new and desire to secure by Letters Patent:

1. An instrument comprising a casing having an internally threaded front end portion, a housing in front of said casing and having its rear portion screwed into the front end of the casing. said housing being formed with a longitudinal bore having its rear portion enlarged and forming a recess, the rear portion of the wall of said recess being formed with oppositely disposed openings, a tool carrier slidable longitudinally through the bore and having a head at its rear end fitting snugly in said recess and formed with .a 4transverse opening aligned with the opposed openings of the housing, a spring in said recess coiled about said tool holder and acting upon the l head to urge the tool holder rearwardly, a pin passing through the opening in the head with end portions projecting therefrom and loosely fitting into the opposed openings of the housing and limiting the longitudinal movement of said tool holder, a plunger slidable longitudinally in said casing back of said tool holder and formed with a pocket leading from its rear end, a rotatable shaft extending longitudinally in said casing axially thereof with its front end extending into said pocket, a cam surrounding the front end of said shaft and turning therewith in the pocket', a bushing arranged in said pocket and loosely surrounding said shaft and having its front end engaged by said cam for intermittently shifting the plunger rearwardly during the rotation of the shaft, a collar surrounding said shaft and secured in said casing and spaced rearwardly from said plunger, a spring in said casing surrounding said shaft between the collar and the plunger and serving to drive the plunger forwardly into striking contact with the tool holder between rearward movements of the plunger by the action of said cam, and means for connecting the rear end of the shaft with a rotary drive shaft.

2. An instrument comprising a cylindrical casing open at its front end and also at its rear end. a housing extending from the front end of the casing and having its rear portion removably connected with the casing, said housing being formed with a longitudinal bore having its rear portion enlarged and forming a recess, said vrecess having opposed wall portions formed with openings, a tool holder slidable longitudinally in said bore and having a head at its rear end slidable longitudinally in said recess and carrying a transverse pin having ends projecting from the head and loosely fitting in the openings to limit the longitudinal movement of the tool holder, a spring urging said tool holder rearwardly, a plunger slidable longitudinally in said casing and held against rotation, said plunger being formed with a pocket leading from its rear end, a bushing secured in said pocket and spaced from the front end thereof, a rotatable shaft extending longitudinally in said casing and having its front end passing through said housing and carrying a cam acting upon the front end of the bushing t'o intermittently shift the plunger rearwardly during the rotation of the shaft, a spring urging said plunger forwardly for striking engagement with the head of the tool holder between rearward movements of the plunger by said cam, and a removable closure for the rear end of the casing rotatably mounting said shaft,

3. An instrument comprising a cylindrical casing open at its front and rear ends and having an intermediate portion inwardly thickened and forming a bore, a housing secured in the forward end of said casing and projecting forwardly therefrom, a tool holder slidable longitudinally through said housing and having a head at its rear end, a spring urging said tool holder rearwardly, a pin limiting the, longitudinal movement of the tool holder, a plunger slidable longitudinally in the bore of said casing and held against rotation, said plunger being formed with a pocket leading from its rear. end and internally threaded from its rear end for a portion of its length, a bushing screwed into said pocket and having an annular iiiange about its rear end abutting the rear end oi the plunger, the front end of said bushingr being spaced from the front end of the` poket'and formed, with a cireumferentially extending can; surface, a rotatable shaft extending longitudinally in said casing with its front end portion passing through said bushingand carrying a cam disposed between the front ends o f the bushing and the pocket and coacting with the cam surface of the bushing for intermittently Shifting the plunger rearwardly during the rotation of the shaft', a collar surrounding said shaft and secured in the rear end portion of said casing, a spring surrounding said shaft and bearing against said collar and the rear flange of the bushing for shifting the plunger forwardly into striking contact with the head of the tool holder between rearward movements of the cam during the rotation of the shaft, a closure for the rear end of the casing surrounding and rotatably supporting the shaft and for holding the shaft against longitudinal movement, and a coupling for connecting the rear end of the shaft with a rotary drive shaft.

ALFRED A. BAMBERGER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

